Question: Solve for $q$ : $-24 + q = -20$
Answer: Add $24$ to both sides: $ \begin{eqnarray} \\ -24 + q &=& -20 \\ \\ {+24} && {+24} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{-24 + q} &\hphantom{=}& \hphantom{-20} \\ q &=& -20 {+ 24} \\ \end{eqnarray} $ Simplify. $ q = 4$